Monitoring Deformations Of A Wooden Church Tower By Laser Scanning

Conference paper (2021)

Authors

Linh Truong-Hong Optical and Laser Remote Sensing - CEG
R.C. Lindenbergh Optical and Laser Remote Sensing - CEG
W.F. Gard Bio-based Structures & Materials - CEG
J.W.G. van de Kuilen Technische Universität München, Bio-based Structures & Materials - CEG
Research Group
Optical and Laser Remote Sensing (CEG) (TU Delft)
Copyright: © 2021 Linh Truong-Hong, R.C. Lindenbergh, Pieter Woudenberg, W.F. Gard, J.W.G. van de Kuilen
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Published Date

2021

Language

English

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Faculty

Civil Engineering & Geosciences

Department

Geoscience and Remote Sensing

Research Group

Optical and Laser Remote Sensing

Abstract

Churches are part of heritage structures that take an important role in Europe ́s cultural identity. As such, these structures must be protected to prevent catastrophic collapse and any damage must be reported timely to establish planning to maintenance and restoration. This can be achievable when the churches are monitored periodically with regular intervals. However, this monitoring strategy has not been available in most of the Europe’s churches for a number of reasons, complexity of the structures and limited budget are just two of them. Laser scanning has been widely used in capturing rich three-dimensional (3D) topographic data of visible surfaces of a structure with high accuracy. This paper presents a methodology to determine the shape and possible deviation from verticality of the church’s tower for monitoring deformation using a terrestrial laser scanner. The 500-year old wooden tower of St. Bavo Church in Haarlem, Netherlands is selected as a case study. First, point clouds of the tower captured from different views are registered into the same coordinate system. Second, a RANSAC method is employed to extract point clouds of a whole façades of the tower. Next, a point and surface-based method is proposed to compute the deformation of the surface from its data points. The results indicate that there is slightly different deformation between the tower facades in the same story and in neighbour stories. Moreover, the maximum total relative deformation at Story 7 of the tower by 0.63m.